The Pennsylvania State University, 803 Oswald Tower, University Park, PA, 16802, USA,
Int J Behav Med. 2014 Apr;21(2):282-91. doi: 10.1007/s12529-013-9293-2.
Obesity has become a problem in the USA and identifying modifiable factors at the individual level may help to address this public health concern. A burgeoning literature has suggested that sleep and stress may be associated with obesity; however, little is know about whether these two factors moderate each other and even less is known about whether their impacts on obesity differ by gender.
This study investigates whether sleep and stress are associated with body mass index (BMI) respectively, explores whether the combination of stress and sleep is also related to BMI, and demonstrates how these associations vary across the distribution of BMI values.
We analyze the data from 3,318 men and 6,689 women in the Philadelphia area using quantile regression (QR) to evaluate the relationships between sleep, stress, and obesity by gender.
Our substantive findings include: (1) high and/or extreme stress were related to roughly an increase of 1.2 in BMI after accounting for other covariates; (2) the pathways linking sleep and BMI differed by gender, with BMI for men increasing by 0.77-1 units with reduced sleep duration and BMI for women declining by 0.12 unit with 1 unit increase in sleep quality; (3) stress- and sleep-related variables were confounded, but there was little evidence for moderation between these two; (4) the QR results demonstrate that the association between high and/or extreme stress to BMI varied stochastically across the distribution of BMI values, with an upward trend, suggesting that stress played a more important role among adults with higher BMI (i.e., BMI > 26 for both genders); and (5) the QR plots of sleep-related variables show similar patterns, with stronger effects on BMI at the upper end of BMI distribution.
Our findings suggested that sleep and stress were two seemingly independent predictors for BMI and their relationships with BMI were not constant across the BMI distribution.
肥胖已成为美国的一个问题，确定个体层面上可改变的因素可能有助于解决这一公共卫生问题。大量文献表明，睡眠和压力可能与肥胖有关；然而，人们对这两个因素是否相互调节知之甚少，甚至对它们对肥胖的影响是否因性别而异知之甚少。
本研究调查睡眠和压力是否分别与体重指数（BMI）相关，探讨压力和睡眠的组合是否也与 BMI 相关，并展示这些关联在 BMI 值分布中的变化情况。
我们使用分位数回归（QR）分析了来自费城地区的 3318 名男性和 6689 名女性的数据，以评估性别对睡眠、压力和肥胖之间关系的影响。
我们的实质性发现包括：（1）高压力和/或极度压力与其他协变量一起解释后，BMI 大约增加了 1.2；（2）睡眠与 BMI 之间的关联因性别而异，男性的 BMI 随睡眠持续时间减少而增加 0.77-1 个单位，女性的 BMI 随睡眠质量增加 1 个单位而减少 0.12 个单位；（3）压力和睡眠相关变量存在混杂，但几乎没有证据表明两者之间存在调节作用；（4）QR 结果表明，高压力和/或极度压力与 BMI 之间的关联在 BMI 值分布中随机变化，呈上升趋势，这表明压力在 BMI 较高的成年人（即男女 BMI 均>26）中发挥了更重要的作用；（5）睡眠相关变量的 QR 图显示出类似的模式，在 BMI 分布的较高端对 BMI 的影响更强。
我们的研究结果表明，睡眠和压力是 BMI 的两个看似独立的预测因素，它们与 BMI 的关系在 BMI 分布中并非是恒定不变的。
